Distinguish between National Income, Gross National Product, and Gross Domestic Product and explain which is best as describing an economies health.
Gross National Income is the sum of all goods and services sold by firms registered within an economy over a period of time. This value includes all output made by firms, based domestically but working abroad.
In contrast Gross Domestic Income is the sum of all goods and services sold within the domestic boundaries of an economy over a period of time. This figure includes all outputs made by foreign firms within the domestic economy.
National Income measures the amount of money spent on goods and services within an economy.
National Output = National Expenditure (Aggregate Demand) = National Income
It must be noted that if there is a rise in GDP then Aggregate Demand or National Income has risen above inflation and so this is seen as an indicator for economic health.